U.S. patent number 10,856,368 [Application Number 15/754,343] was granted by the patent office on 2020-12-01 for heating cooker system, inductive heating cooker, and electric apparatus.
This patent grant is currently assigned to Mitsubishi Electric Corporation, Mitsubishi Electric Home Appliance Co., Ltd.. The grantee listed for this patent is Mitsubishi Electric Corporation, Mitsubishi Electric Home Appliance Co., Ltd.. Invention is credited to Jun Bunya, Kazuhiro Kameoka, Ikuro Suga, Miyuki Takeshita, Hayato Yoshino.
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United States Patent |
10,856,368 |
Yoshino , et al. |
December 1, 2020 |
Heating cooker system, inductive heating cooker, and electric
apparatus
Abstract
A heating cooker system includes a first coil configured to
produce a first high-frequency magnetic field by receiving supply
of a first high-frequency current, a first inverter circuit
configured to supply the first high-frequency current to the first
coil, a first heating element positioned in reach of the first
high-frequency magnetic field produced by the first coil to be
inductively heated by the first coil, a second coil configured to
produce a second high-frequency magnetic field by receiving supply
of a second high-frequency current, a second inverter circuit
configured to supply the second high-frequency current to the
second coil, a power receiving coil positioned in reach of the
second high-frequency magnetic field produced by the second coil to
receive electric power from the second coil, and a second heating
element configured to generate heat by the electric power received
by the power receiving coil.
Inventors: |
Yoshino; Hayato (Tokyo,
JP), Bunya; Jun (Tokyo, JP), Suga;
Ikuro (Tokyo, JP), Takeshita; Miyuki (Tokyo,
JP), Kameoka; Kazuhiro (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation
Mitsubishi Electric Home Appliance Co., Ltd. |
Tokyo
Fukaya |
N/A
N/A |
JP
JP |
|
|
Assignee: |
Mitsubishi Electric Corporation
(Tokyo, JP)
Mitsubishi Electric Home Appliance Co., Ltd. (Saitama,
JP)
|
Family
ID: |
1000005218502 |
Appl.
No.: |
15/754,343 |
Filed: |
October 16, 2015 |
PCT
Filed: |
October 16, 2015 |
PCT No.: |
PCT/JP2015/079261 |
371(c)(1),(2),(4) Date: |
February 22, 2018 |
PCT
Pub. No.: |
WO2017/064803 |
PCT
Pub. Date: |
April 20, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180263084 A1 |
Sep 13, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05B
6/1245 (20130101); H05B 6/062 (20130101); A47J
37/0629 (20130101); H05B 6/12 (20130101); A47J
27/004 (20130101); Y02B 40/00 (20130101) |
Current International
Class: |
H05B
6/06 (20060101); H05B 6/12 (20060101); A47J
37/06 (20060101); A47J 27/00 (20060101) |
Field of
Search: |
;219/620 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1107634 |
|
Aug 1995 |
|
CN |
|
102884863 |
|
Jan 2013 |
|
CN |
|
2 600 692 |
|
Jun 2013 |
|
EP |
|
2 959 810 |
|
Dec 2015 |
|
EP |
|
H04-341790 |
|
Nov 1992 |
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JP |
|
H05-040853 |
|
Oct 1993 |
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JP |
|
H07-263132 |
|
Oct 1995 |
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JP |
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H07-318075 |
|
Dec 1995 |
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JP |
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H08-315975 |
|
Nov 1996 |
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JP |
|
2005-190910 |
|
Jul 2005 |
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JP |
|
2006-278150 |
|
Oct 2006 |
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JP |
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2010-262751 |
|
Nov 2010 |
|
JP |
|
2011-004795 |
|
Jan 2011 |
|
JP |
|
2011-033313 |
|
Feb 2011 |
|
JP |
|
2011-113948 |
|
Jun 2011 |
|
JP |
|
2012-104261 |
|
May 2012 |
|
JP |
|
2012-113975 |
|
Jun 2012 |
|
JP |
|
2013-058331 |
|
Mar 2013 |
|
JP |
|
2014-154533 |
|
Aug 2014 |
|
JP |
|
10-2005-0056055 |
|
Jun 2005 |
|
KR |
|
10-2007-0066429 |
|
Jun 2007 |
|
KR |
|
2014/129208 |
|
Aug 2014 |
|
WO |
|
Other References
Office Action dated Sep. 25, 2019 issued in corresponding KR patent
application No. 10-2018-7006820 (and English translation). cited by
applicant .
Office Action dated Oct. 1, 2019 issued in corresponding JP patent
application No. 2017-545063 (and English translation). cited by
applicant .
Office Action dated Feb. 28, 2019 issued in corresponding KR patent
application No. 10-2018-7006820 (and English translation). cited by
applicant .
Office Action dated Mar. 5, 2019 issued in corresponding JP patent
application No. 2017-545063 (and English translation). cited by
applicant .
Office Action dated Jul. 27, 2018 in the corresponding AU patent
application No. 2015411672. cited by applicant .
International Search Report of the International Searching
Authority dated Dec. 28, 2015 for the corresponding International
application No. PCT/JP2015/079261 (and English translation). cited
by applicant .
Office Action dated May 26, 2020 issued in corresponding CN patent
application No. 201580083751.7 (and English translation). cited by
applicant .
Office Action dated Mar. 30, 2020 issued in corresponding KR patent
application No. 10-2018-7006820 (and English translation). cited by
applicant.
|
Primary Examiner: Le; Huyen D
Attorney, Agent or Firm: Posz Law Group, PLC
Claims
The invention claimed is:
1. A heating cooker system comprising: a main body in which a first
coil configured to produce a first high-frequency magnetic field by
receiving supply of a first high-frequency current, a first
inverter circuit configured to supply the first high-frequency
current to the first coil, a second coil configured to produce a
second high-frequency magnetic field by receiving supply of a
second high-frequency current, and a second inverter circuit
provided independently of the first inverter circuit and configured
to supply the second high-frequency current to the second coil, are
arranged below a top plate of the main body; and an electric
apparatus including a first heating element positioned in reach of
the first high-frequency magnetic field produced by the first coil
across the top plate to be inductively heated by the first coil, a
power receiving coil positioned in reach of the second
high-frequency magnetic field produced by the second coil across
the top plate to receive electric power from the second coil, and a
second heating element configured to generate heat by the electric
power received by the power receiving coil, wherein, in a top view,
the first heating element is formed into a rectangular shape, the
first coil has a width equal to each of short sides of the first
heating element, and the second coil is positioned to flank two
long sides of the first heating element.
2. The heating cooker system of claim 1, wherein the electric
apparatus is detachably supported by the main body.
3. The heating cooker system of claim 1, comprising: a controller
configured to control driving of the first inverter circuit in
accordance with heating power for inductively heating the first
heating element and control driving of the second inverter circuit
in accordance with the electric power to be transmitted to the
power receiving coil.
4. The heating cooker system of claim 3, wherein the electric
apparatus includes a temperature sensor configured to detect a
temperature in a heating chamber in which a heating target is
stored, and a transmitting device configured to transmit
information of the temperature detected by the temperature sensor,
wherein the main body includes a receiving device configured to
receive the information of the temperature transmitted from the
transmitting device, and wherein the controller controls the
driving of the first inverter circuit and the driving of the second
inverter circuit in accordance with the information of the
temperature.
5. The heating cooker system of claim 3, wherein the main body
includes the top plate on which the electric apparatus is placed,
and wherein the first coil is included in a plurality of coils
provided under the top plate, wherein the controller detects
whether the first heating element or the power receiving coil is
placed above any of the plurality of coils, wherein the controller
causes each of the plurality of coils on which the first heating
element is detected to function as the first coil to inductively
heat the first heating element, and wherein the controller causes
each of the plurality of coils on which the power receiving coil is
detected to function as the second coil to transmit the electric
power to the power receiving coil.
6. The heating cooker system of claim 5, wherein the top plate is
formed with a heating area indicating a position at which a heating
target is to be placed, and the plurality of coils is provided for
the heating area.
7. The heating cooker system of claim 6, wherein the plurality of
coils includes an inner circumferential coil positioned at a center
of the heating area, and an outer circumferential coil positioned
around the inner circumferential coil.
8. The heating cooker system of claim 6, wherein the coils of the
plurality of coils are different in diameter and concentrically
positioned.
9. The heating cooker system of claim 5, wherein the coils of the
plurality of coils are evenly dispersedly positioned under the top
plate.
10. The heating cooker system of claim 1, wherein the electric
apparatus includes a cooking tray on which a heating target is
placed, wherein the first heating element is positioned on a bottom
surface of the electric apparatus, wherein the cooking tray is
positioned in contact with the first heating element, and wherein
the second heating element is positioned above the cooking
tray.
11. The heating cooker system of claim 1, wherein the electric
apparatus includes a drive mechanism configured to move the second
heating element in a vertical direction.
12. An inductive heating cooker comprising: a first coil arranged
below a top plate and configured to produce a first high-frequency
magnetic field for inductively heating a rectangular-shaped area in
a top view first heating element of an electric apparatus
positioned on the top plate, the first coil being configured to
produce the first high-frequency magnetic field by receiving supply
of a first high-frequency current; a first inverter circuit
configured to supply the first high-frequency current to the first
coil; a second coil arranged below the top plate and configured to
produce a second high-frequency magnetic field for transmitting
power to a power receiving coil of an electric apparatus positioned
over the top plate, the second coil being configured to produce the
second high-frequency magnetic field by receiving supply of a
second high-frequency current; a second inverter circuit provided
independently of the first inverter circuit and configured to
supply the second high-frequency current to the second coil; and a
controller configured to perform a heating operation of controlling
driving of the first inverter circuit to inductively heat the first
heating element, and a power transmitting operation of controlling
driving of the second inverter circuit to transmit electric power
to the power receiving coil, wherein, in the top view, the first
coil has a width equal to each of short sides of the first heating
element, and the second coil is positioned to flank two long sides
of the first heating element.
13. An electric apparatus adapted to be positioned on a top plate
of an inductive heating cooker, the electric apparatus comprising:
a heating chamber configured to store a heating target; a cooking
tray on which the heating target is placed; a first heating element
formed into a rectangular shape in a top view and positioned on a
bottom surface of the heating chamber to be in contact with the
cooking tray, wherein the first heating element is configured to be
inductively heated by a first high-frequency magnetic field
produced by a first coil, which receives supply of a first
high-frequency current from a first inverter circuit of the
inductive heating cooker; a power receiving coil positioned to
flank two long sides of the first heating element in a top view and
configured to receive electric power through electromagnetic
induction or magnetic field resonance from a second high-frequency
magnetic field produced by a second coil which receives supply of a
second high-frequency current from a second inverter circuit of the
inductive heating cooker that is provided independently of the
first inverter circuit; a second heating element positioned above
the cooking tray and configured to generate heat by the electric
power received by the power receiving coil; a temperature sensor
configured to detect a temperature in the heating chamber; and a
transmitting device configured to transmit information of the
temperature detected by the temperature sensor to the inductive
heating cooker.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application is a U.S. national stage application of
PCT/JP2015/079261 filed on Oct. 16, 2015, the contents of which are
incorporated herein by reference.
TECHNICAL FIELD
The present invention relates to a heating cooker system, an
inductive heating cooker, and an electric apparatus using inductive
heating and heating through non-contact power transmission.
BACKGROUND ART
A high-frequency inductive heating cooker including an inductive
heating coil that inductively heats a cooking container, a power
receiving coil that is electromagnetically induced by a power
feeding coil, and a heating unit that is supplied with power by the
power receiving coil, and in which the inductive heating coil and
the power feeding coil share a power supply unit has been proposed
(see Patent Literature 1, for example).
CITATION LIST
Patent Literature
Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 4-341790
SUMMARY OF INVENTION
Technical Problem
The conventional high-frequency inductive heating cooker uses the
same power supply unit to supply power to the heating coil and the
power feeding coil. That is, in the conventional high-frequency
inductive heating cooker, a coil switching relay alternately
switches between supply of power to the inductive heating coil from
the power supply unit and supply of power to the power feeding coil
from the power supply unit. This raises an issue that inductive
heating with the inductive heating coil and heating with electric
power received from the power feeding coil through non-contact
power transmission are not simultaneously executable.
Further, in the conventional high-frequency inductive heating
cooker, the inductive heating coil and the power feeding coil are
connected in series to supply power to the inductive heating coil
and the power feeding coil from the single power supply unit. This
raises an issue that the heating through inductive heating and the
heating through non-contact power transmission are not
independently controllable.
The present invention has been made to address the above-described
issues, and an object of the present invention is to obtain a
heating cooker system, an inductive heating cooker, and an electric
apparatus capable of simultaneously and independently controlling
the heating through inductive heating and the heating through
non-contact power transmission.
Solution to Problem
A heating cooker system according to an embodiment of the present
invention includes a first coil configured to produce a first
high-frequency magnetic field by receiving supply of a first
high-frequency current; a first inverter circuit configured to
supply the first high-frequency current to the first coil; a first
heating element positioned in reach of the first high-frequency
magnetic field produced by the first coil to be inductively heated
by the first coil; a second coil configured to produce a second
high-frequency magnetic field by receiving supply of a second
high-frequency current; a second inverter circuit provided
independently of the first inverter circuit and configured to
supply the second high-frequency current to the second coil; a
power receiving coil positioned in reach of the second
high-frequency magnetic field produced by the second coil to
receive electric power from the second coil; and a second heating
element configured to generate heat by the electric power received
by the power receiving coil.
Advantageous Effects of Invention
The heating cooker system according to the embodiment of the
present invention includes the first inverter circuit, which
supplies the first high-frequency current to the first coil that
inductively heats the first heating element, and the second
inverter circuit, which supplies the second high-frequency current
to the second coil that transmits the electric power to the power
receiving coil.
Accordingly, the heating through inductive heating and the heating
through non-contact power transmission are simultaneously
executable. Further, the heating through inductive heating and the
heating through non-contact power transmission are independently
controllable.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is an exploded perspective view illustrating a main body of
an inductive heating cooker in a heating cooker system according to
Embodiment 1.
FIG. 2 is a diagram illustrating a first heating unit of the
inductive heating cooker according to Embodiment 1.
FIG. 3 is a block diagram illustrating drive circuits of the first
heating unit of the inductive heating cooker according to
Embodiment 1.
FIG. 4 is a diagram illustrating one of the drive circuits of the
inductive heating cooker according to Embodiment 1.
FIG. 5 is a block diagram illustrating a configuration of the main
body of the inductive heating cooker and an electric apparatus in
the heating cooker system according to Embodiment 1.
FIG. 6 is a top view schematically illustrating a configuration of
the electric apparatus of the heating cooker system according to
Embodiment 1.
FIG. 7 is a diagram illustrating a modified example of a power
receiving coil of the electric apparatus according to Embodiment
1.
FIG. 8 is a diagram illustrating the modified example of the power
receiving coil of the electric apparatus according to Embodiment
1.
FIG. 9 is a diagram illustrating another one of the drive circuits
of the inductive heating cooker according to Embodiment 1.
FIG. 10 is a diagram illustrating the other ones of the drive
circuits of the inductive heating cooker according to Embodiment
1.
FIG. 11 is a diagram illustrating another first heating unit of the
inductive heating cooker according to Embodiment 1.
FIG. 12 is a block diagram illustrating a configuration of an
electric apparatus of a heating cooker system according to
Embodiment 2.
FIG. 13 is a block diagram illustrating a configuration of an
electric apparatus of a heating cooker system according to
Embodiment 3.
FIG. 14 is a block diagram illustrating the configuration of the
electric apparatus of the heating cooker system according to
Embodiment 3.
FIG. 15 is a top view schematically illustrating the configuration
of the electric apparatus of the heating cooker system according to
Embodiment 3.
FIG. 16 is a diagram illustrating a first heating unit of an
inductive heating cooker according to Embodiment 3.
FIG. 17 is a load determining characteristic graph based on the
relationship between a coil current and an input current in an
inductive heating cooker according to Embodiment 4.
FIG. 18 is a perspective view illustrating a schematic
configuration of a main body of an inductive heating cooker
according to Embodiment 5.
DESCRIPTION OF EMBODIMENTS
Embodiment 1
(Configuration)
FIG. 1 is an exploded perspective view illustrating a main body of
an inductive heating cooker in a heating cooker system according to
Embodiment 1.
As illustrated in FIG. 1, an upper portion of a main body 100 of
the inductive heating cooker includes a top plate 4 on which a
load, such as a heating target 5 like a pot or an electric
apparatus 200, is placed. With FIG. 1, a description will be given
of an example in which the heating target 5 is placed as the load.
The top plate 4 includes a first heating area 1, a second heating
area 2, and a third heating area 3 as heating areas for inductively
heating the heating target 5. Corresponding to the respective
heating areas, a first heating unit 11, a second heating unit 12,
and a third heating unit 13 are provided to enable inductive
heating of the heating target 5 placed on one of the heating
areas.
In Embodiment 1, the first heating unit 11 and the second heating
unit 12 are provided to be laterally aligned on the front side of
the main body, and the third heating unit 13 is provided
substantially at the center of the main body on the rear side of
the main body.
The arrangement of the heating areas is not limited thereto. For
example, the three heating areas may be arranged to be aligned
laterally in a substantially linear manner. Further, the first
heating unit 11 and the second heating unit 12 may be arranged such
that the respective centers thereof are different in position in
the depth direction.
The whole of top plate 4 is entirely made of an infrared
transmitting material, such as heat-resistant reinforced glass or
crystallized glass, and is watertightly fixed to an outer
circumference of an upper opening of the main body 100 of the
inductive heating cooker via a rubber packing or sealing material.
On the top plate 4, circular pot position marks roughly indicating
pot placement positions are formed by painting or printing, for
example, corresponding to respective heating ranges (the heating
areas) of the first heating unit 11, the second heating unit 12,
and the third heating unit 13.
The front side of the top plate 4 is provided with an operation
unit 40a, an operation unit 40b, and an operation unit 40c
(hereinafter occasionally collectively referred to as the operation
units 40) each as an input device for setting heating power to be
input (electric power to be input) and a cooking menu (such as
boiling mode, frying mode, or electric apparatus heating mode) when
heating the heating target 5 with the corresponding one of the
first heating unit 11, the second heating unit 12, and the third
heating unit 13. Further, a display unit 41a, a display unit 41b,
and a display unit 41c for displaying information such as the
operating state of the main body 100 and details of inputs and
operations from the operation units 40 are provided near the
operation units 40 as reporting units 42.
The configurations of the operation units 40a to 40c and the
display units 41a to 41c are not particularly limited. For example,
the operation units 40a to 40c and the display units 41a to 41c may
be provided for the respective heating areas, or an operation unit
40 and a display unit 41 may be provided for the heating areas as a
whole. The operation units 40a to 40c are formed of mechanical
switches, such as push switches or tactile switches, or touch
switches that detect an input operation based on a change in
capacitance of an electrode, for example. Further, the display
units 41a to 41c are formed of liquid crystal devices (LCDs) or
LEDs, for example.
The following description will be given of a case in which a
display-and-operation unit 43 configured to integrate the operation
units 40 and the display units 41 is provided. The
display-and-operation unit 43 is formed of a touch panel having
touch switches arranged on an upper surface of an LCD, for
example.
Under the top plate 4, the main body 100 includes therein the first
heating unit 11, the second heating unit 12, and the third heating
unit 13, each of which is formed of coils.
At least one of the first heating unit 11, the second heating unit
12, and the third heating unit 13 may be formed of a type of
electric heater that performs heating by radiation, for example (a
nichrome wire, a halogen heater, or a radiant heater, for
instance).
Each of the coils is formed by winding a conductive wire made of a
given metal (copper or aluminum, for example) coated with an
insulating film. Each of the coils is supplied with high-frequency
power by a drive circuit 50, and thereby produces a high-frequency
magnetic field.
The main body 100 of the inductive heating cooker includes therein
drive circuits 50, which supply high-frequency power to the coils
of the first heating unit 11, the second heating unit 12, and the
third heating unit 13, and a control unit 45 for controlling the
operation of the entire inductive heating cooker including the
drive circuits 50.
FIG. 2 is a diagram illustrating the first heating unit of the
inductive heating cooker according to Embodiment 1.
In FIG. 2, the first heating unit 11 is formed of an inner
circumferential coil 11a positioned at the center thereof and outer
circumferential coils 11b and 11c positioned around the inner
circumferential coil 11a. The outer circumference of the first
heating unit 11 has a substantially circular shape corresponding to
the first heating area 1.
The inner circumferential coil 11a is formed of an inner
circumferential inner coil 111a and an inner circumferential outer
coil 112a, which are positioned substantially concentrically with
each other. Each of the inner circumferential inner coil 111a and
the inner circumferential outer coil 112a has a circular plane
shape, and is formed of a conductive wire made of a given metal
(copper or aluminum, for example) coated with an insulating film
and wound in the circumferential direction. The inner
circumferential inner coil 111a and the inner circumferential outer
coil 112a are connected in series and subjected to drive control of
one of the drive circuits 50. The inner circumferential inner coil
111a and the inner circumferential outer coil 112a may be connected
in parallel, and may respectively be driven with independent drive
circuits (inverter circuits).
The outer circumferential coil 11b is formed of an outer
circumferential left coil 111b and an outer circumferential right
coil 112b. The outer circumferential coil 11c is formed of an outer
circumferential upper coil 111c and an outer circumferential lower
coil 112c. The outer circumferential left coil 111b and the outer
circumferential right coil 112b are connected in series and
subjected to drive control of one of the drive circuits 50.
Further, the outer circumferential upper coil 111c and the outer
circumferential lower coil 112c are connected in series and
subjected to drive control of one of the drive circuits 50.
The outer circumferential left coil 111b, the outer circumferential
right coil 112b, the outer circumferential upper coil 111c, and the
outer circumferential lower coil 112c (hereinafter also referred to
as "the outer circumferential coils") are positioned around the
inner circumferential coil 11a to substantially follow a circular
outer shape of the inner circumferential coil 11a.
Each of the four outer circumferential coils has a substantially
quarter arcuate shape (banana or cucumber shape) in a plan view,
and is formed of a conductive wire made of a given metal (copper or
aluminum, for example) coated with an insulating film and wound
along the quarter arcuate shape of the outer circumferential coil.
That is, each of the outer circumferential coils is formed to
extend substantially along the circular plane shape of the inner
circumferential coil 11a in a quarter arc-shaped area adjacent to
the inner circumferential coil 11a. The number of the outer
circumferential coils is not limited to four. Further, the shape of
each of the outer circumferential coils is not limited to the
above-described one. For example, a configuration using a plurality
of circular outer circumferential coils may be employed.
FIG. 3 is a block diagram illustrating the drive circuits of the
first heating unit of the inductive heating cooker according to
Embodiment 1.
As illustrated in FIG. 3, the first heating unit 11 is subjected to
drive control of drive circuits 50a, 50b, and 50c. That is, the
inner circumferential inner coil 111a and the inner circumferential
outer coil 112a forming the inner circumferential coil 11a are
subjected to drive control of the drive circuit 50a. Further, the
outer circumferential left coil 111b and the outer circumferential
right coil 112b forming the outer circumferential coil 11b are
subjected to drive control of the drive circuit 50b. Further, the
outer circumferential upper coil 111c and the outer circumferential
lower coil 112c forming the outer circumferential coil 11c are
subjected to drive control of the drive circuit 50c.
The control unit 45 is formed of a device such as a microcomputer
or a digital signal processor (DSP). Based on information such as
details of operations of the display-and-operation unit 43, the
control unit 45 controls each of the drive circuits 50a, 50b, and
50c. The control unit 45 further displays information on the
display-and-operation unit 43 in accordance with factors such as
the operating state.
FIG. 4 is a diagram illustrating one of the drive circuits of the
inductive heating cooker according to Embodiment 1. The drive
circuits 50, which are provided for the respective heating units,
may have the same circuit configuration, or may have different
circuit configurations for the respective heating units. FIG. 4
illustrates the drive circuit 50a that drives the inner
circumferential coil 11a.
As illustrated in FIG. 4, the drive circuit 50a includes a
direct-current power supply circuit 22, an inverter circuit 23, and
a resonant capacitor 24a.
An input current detecting unit 25a, which is formed of a current
sensor, for example, detects a current input to the direct-current
power supply circuit 22 from an alternating-current power supply
(commercial power supply) 21, and outputs a voltage signal
corresponding to the value of the input current to the control unit
45.
The direct-current power supply circuit 22, which includes a diode
bridge 22a, a reactor 22b, and a smoothing capacitor 22c, converts
an alternating-current voltage input thereto from the
alternating-current power supply 21 into a direct-current voltage,
and outputs the direct-current voltage to the inverter circuit
23.
The inverter circuit 23 is a so-called half-bridge inverter, in
which IGBTs 23a and 23b serving as switching elements are connected
in series with outputs of the direct-current power supply circuit
22, and diodes 23c and 23d are connected in parallel with the IGBTs
23a and 23b, respectively, as flywheel diodes. The IGBTs 23a and
23b are driven on and off by a drive signal output from the control
unit 45. The control unit 45 outputs the drive signal, which
alternately turns on and off the IGBTs 23a and 23b by placing the
IGBT 23b in the OFF state when the IGBT 23a is turned on and
placing the IGBT 23b in the ON state when the IGBT 23a is turned
off. Thereby, the inverter circuit 23 converts the direct-current
power output from the direct-current power supply circuit 22 into
alternating-current power having a high frequency ranging from
approximately 20 kHz to approximately 100 kHz, and supplies the
power to a resonant circuit formed of the inner circumferential
coil 11a and the resonant capacitor 24a.
With the resonant capacitor 24a connected in series with the inner
circumferential coil 11a, the resonant circuit has a resonant
frequency according to factors such as the inductance of the inner
circumferential coil 11a and the capacitance of the resonant
capacitor 24a. When magnetic coupling with the heating target 5 (a
metal load) occurs, the inductance of the inner circumferential
coil 11a changes in accordance with characteristics of the metal
load, and the resonant frequency of the resonant circuit changes in
accordance with the change in the inductance.
With this configuration, a high-frequency current of approximately
tens of amperes flows through the inner circumferential coil 11a,
and the heating target 5 placed on a part of the top plate 4
immediately above the inner circumferential coil 11a is inductively
heated by a high-frequency magnetic flux produced by the flowing
high-frequency current. Each of the IGBTs 23a and 23b serving as a
switching element is formed with a semiconductor made of a
silicon-based material, for example, but may be formed with a
wideband gap semiconductor made of a material such as a silicon
carbide-based material or a gallium nitride-based material.
With the use of the wideband gap semiconductor for the switching
element, it is possible to reduce power supply loss of the
switching element, and realize favorable heat transfer from the
drive circuit even if the switching frequency (driving frequency)
is increased to a high frequency (high speed). Accordingly, it is
possible to reduce the size of heat transfer fins of the drive
circuit, and thus to reduce the size and cost of the drive
circuit.
A coil current detecting unit 25b is connected to the resonant
circuit formed of the inner circumferential coil 11a and the
resonant capacitor 24a. The coil current detecting unit 25b, which
is formed of a current sensor, for example, detects the current
flowing through the inner circumferential coil 11a and outputs a
voltage signal corresponding to the value of the coil current to
the control unit 45.
The drive circuit 50a that drives the inner circumferential coil
11a has been described with FIG. 4. A configuration similar to the
configuration of the drive circuit 50a is also applicable to the
drive circuit 50b that drives the outer circumferential coil 11b
and the drive circuit 50c that drives the outer circumferential
coil 11c. The drive circuits 50a, 50b, and 50c may be connected in
parallel with the alternating-current power supply 21.
FIG. 5 is a block diagram illustrating a configuration of the main
body of the inductive heating cooker and the electric apparatus in
the heating cooker system according to Embodiment 1.
In FIG. 5, the heating cooker system includes the main body 100 of
the inductive heating cooker and the electric apparatus 200. FIG. 5
illustrates a state in which the electric apparatus 200 is placed
on the top plate 4 of the main body 100. Further, FIG. 5
schematically illustrates a longitudinal section of the main body
100 and the electric apparatus 200 viewed from a front surface side
thereof in a state in which the electric apparatus 200 is placed on
the first heating unit 11.
In FIG. 5, the main body 100 includes the inner circumferential
coil 11a and the outer circumferential coil 11b (the outer
circumferential left coil 111b and the outer circumferential right
coil 112b) positioned under the top plate 4. Illustration of the
outer circumferential upper coil 111c and the outer circumferential
lower coil 112c forming the outer circumferential coil 11c is
omitted in FIG. 5. In FIG. 5, arrows illustrated around the inner
circumferential coil 11a and a magnetic member 60a, arrows
illustrated around the outer circumferential left coil 111b and a
power receiving coil 65, and arrows illustrated around the outer
circumferential right coil 112b and a power receiving coil 65
indicate magnetic flux lines.
The main body 100 is provided with a first transmitting and
receiving unit 30a that communicates with the electric apparatus
200. The first transmitting and receiving unit 30a is formed of a
wireless communication interface conforming to a given
communication standard, such as Wi-Fi (registered trademark),
Bluetooth (registered trademark), infrared communication, or near
field communication (NFC), for example. The first transmitting and
receiving unit 30a bidirectionally communicates information with a
second transmitting and receiving unit 30b of the electric
apparatus 200.
The electric apparatus 200 is an apparatus that cooks a food 70,
such as fish, for example. The electric apparatus 200 is placed on
the top plate 4 of the main body 100. A heating chamber 210 for
storing the food 70 is formed in a housing of the electric
apparatus 200. The electric apparatus 200 includes the magnetic
member 60a, a cooking tray 60b, an upper heater 61, a temperature
sensor 62, power receiving coils 65, and the second transmitting
and receiving unit 30b.
The magnetic member 60a is made of a magnetic material, such as
iron, for example, and is positioned on a bottom surface of the
electric apparatus 200.
The cooking tray 60b has an upper surface having corrugated
irregularities, for example, and the food 70, such as fish, for
example, is placed on the upper surface. The cooking tray 60b is
positioned in contact with an upper surface of the magnetic member
60a, for example, and the food 70 is placed on the cooking tray
60b. The cooking tray 60b is made of a non-magnetic metal, such as
aluminum, for example, and is thermally coupled (joined) with the
magnetic member 60a. The position of the cooking tray 60b is not
limited to the upper surface of the magnetic member 60a, and it
suffices if the cooking tray 60b is disposed at a position to which
the heat from the magnetic member 60a is transferred.
The power receiving coils 65 are positioned on the bottom surface
of the electric apparatus 200. Each of the power receiving coils 65
is formed of a conductive wire made of a given metal (copper or
aluminum, for example) coated with an insulating film and wound in
the circumferential direction. When positioned in reach of a
high-frequency magnetic field produced by the outer circumferential
coil 11b in the main body 100, the power receiving coil 65 receives
electric power through electromagnetic induction or magnetic field
resonance.
The upper heater 61 is connected to the power receiving coils 65 by
wires 61a. The upper heater 61 is formed of a heating element that
generates heat by the electric power received by the power
receiving coils 65. For example, a sheathed heater being a
resistance heating element is employed as the upper heater 61. A
specific configuration of the upper heater 61 is not limited
thereto, and a given heating element such as a halogen heater or a
far-infrared heater may be employed.
The temperature sensor 62 is positioned in the heating chamber 210
to detect the temperature in the heating chamber 210. For example,
a platinum resistance temperature detector, a thermistor, or a
thermocouple is employed as the temperature sensor 62. A plurality
of temperature sensors 62 may be provided as necessary. Further,
the temperature sensor 62 is not necessarily positioned on a wall
surface of the heating chamber 210, and may be provided on a top
surface or a bottom surface of the heating chamber 210 or on the
cooking tray 60b as necessary. Further, a non-contact temperature
sensor 62 may be provided which detects the amount of infrared rays
radiated from the food 70 to detect the surface temperature of the
food 70.
The second transmitting and receiving unit 30b is formed of a
wireless communication interface conforming to the communication
standard of the first transmitting and receiving unit 30a. The
second transmitting and receiving unit 30b bidirectionally
communicates information with the first transmitting and receiving
unit 30a of the main body 100. The second transmitting and
receiving unit 30b transmits to the first transmitting and
receiving unit 30a information such as the information of the
temperature detected by the temperature sensor 62, information
uniquely added to the electric apparatus 200, information
indicating the apparatus type of the electric apparatus 200, and
information related to apparatus specifications of the electric
apparatus 200.
The magnetic member 60a and the power receiving coils 65 of the
electric apparatus 200 are positioned at respective positions
corresponding to the coils positioned under the top plate 4 of the
main body 100.
For example, the magnetic member 60a and the power receiving coils
65 are disposed at respective positions at which the positional
relationship between the magnetic member 60a and the power
receiving coils 65 corresponds to the positional relationship
between the inner circumferential coil 11a and the outer
circumferential coils 11b and 11c of the first heating unit 11. One
example thereof will be described with reference to FIG. 6.
FIG. 6 is a top view schematically illustrating a configuration of
the electric apparatus of the heating cooker system according to
Embodiment 1.
As illustrated in FIG. 6, in the electric apparatus 200, the
magnetic member 60a and the power receiving coils 65 are positioned
under the cooking tray 60b having a circular shape, for
example.
The magnetic member 60a is formed into a disc shape having an outer
diameter substantially the same as the outer diameter of the inner
circumferential coil 11a of the main body 100. That is, in a state
in which the electric apparatus 200 is placed on the top plate 4 of
the main body 100, the magnetic member 60a of the electric
apparatus 200 is positioned to be superimposed on the inner
circumferential coil 11a of the main body 100 in the vertical
direction. Further, the magnetic member 60a has a shape not
superimposed on the outer circumferential coils 11b and 11c in the
vertical direction.
Four power receiving coils 65 are provided around the magnetic
member 60a to correspond to the outer circumferential coils 11b and
11c of the main body 100. Each of the four power receiving coils 65
has a shape substantially the same as the shape of each of the
outer circumferential coils 11b and 11c of the main body 100. That
is, each of the four power receiving coils 65 has a substantially
quarter arcuate shape (banana or cucumber shape) in a plan view,
and is formed of a conductive wire made of a given metal (copper or
aluminum, for example) coated with an insulating film and wound
along the quarter arcuate shape of the power receiving coil 65.
It is desirable that the power receiving coils 65 of the electric
apparatus 200 are positioned to be only superimposed on the outer
circumferential coils 11b and 11c of the main body 100 and not to
be superimposed on the inner circumferential coil 11a of the main
body 100 in the vertical direction.
The positions of the power receiving coils 65 are not limited to
the positions illustrated in FIG. 6, and it suffices if the power
receiving coils 65 are disposed at respective positions at least
partially above the outer circumferential coils 11b and 11c when
the magnetic member 60a is positioned above the inner
circumferential coil 11a. Further, the number of the power
receiving coils 65 is not limited to the above-described number,
and it suffices if at least one power receiving coil 65 is
provided. Further, a configuration provided with a plurality of
power receiving coils 65 for one outer circumferential coil may be
employed.
With the above-described configuration, when the electric apparatus
200 is placed on the top plate 4 of the main body 100, the magnetic
member 60a and the inner circumferential coil 11a are positioned to
be superimposed on each other in the vertical direction. Further,
when a high-frequency current is supplied to the inner
circumferential coil 11a from the drive circuit 50a, the magnetic
member 60a is inductively heated by a high-frequency magnetic flux
(high-frequency magnetic field) produced by the inner
circumferential coil 11a. The heat generated by the magnetic member
60a is transferred to the cooking tray 60b, which is thermally
coupled with the magnetic member 60a. Thereby, the food 70 placed
on the cooking tray 60b is heated from below.
Further, when the electric apparatus 200 is placed on the top plate
4 of the main body 100, the power receiving coils 65 and the outer
circumferential coils 11b and 11c are positioned to be superimposed
on each other in the vertical direction. Further, when
high-frequency currents are supplied to the outer circumferential
coils 11b and 11c from the drive circuits 50b and 50c,
respectively, high-frequency magnetic fluxes (high-frequency
magnetic fields) are produced by the outer circumferential coils
11b and 11c. With the high-frequency magnetic fluxes
(high-frequency magnetic fields) produced by the outer
circumferential coils 11b and 11c, electric power (electromotive
force) due to electromagnetic induction is generated in the power
receiving coils 65 of the electric apparatus 200. The electric
power generated in the power receiving coils 65 is then supplied to
the upper heater 61. Thereby, the upper heater 61 generates heat,
and the food 70 placed on the cooking tray 60b is heated from above
by thermal radiation.
As described above, the inner circumferential coil 11a of the main
body 100 is used as an inductive heating coil for heating the
magnetic member 60a of the electric apparatus 200. Further, the
outer circumferential coils 11b and 11c of the main body 100 are
used as power feeding coils for performing non-contact power
transmission to the upper heater 61 of the electric apparatus
200.
The high-frequency current supplied to the inner circumferential
coil 11a from the drive circuit 50a corresponds to a "first
high-frequency current" of the present invention.
Further, the high-frequency magnetic flux (high-frequency magnetic
field) produced by the inner circumferential coil 11a corresponds
to a "first high-frequency magnetic field" of the present
invention.
The high-frequency current supplied to the outer circumferential
coils 11b and 11c from the drive circuits 50b and 50c corresponds
to a "second high-frequency current" of the present invention.
Further, the high-frequency magnetic flux (high-frequency magnetic
field) produced by the outer circumferential coils 11b and 11c
corresponds to a "second high-frequency magnetic field" of the
present invention.
Although not illustrated in FIGS. 5 and 6, it is desirable to
provide ferrite on lower surfaces of the inner circumferential coil
11a and the outer circumferential coils 11b and 11c of the main
body 100 as a magnetic member. It is also desirable to similarly
provide ferrite on upper surfaces of the power receiving coils 65
of the electric apparatus 200.
Providing ferrite to the outer circumferential coils 11b and 11c
used as the power feeding coils facilitates interlinkage of the
high-frequency magnetic fluxes, thereby reducing magnetic flux
leakage. It is thereby possible to feed the high-frequency power to
the power receiving coils 65 more efficiently, thereby enabling an
increase in power supply conversion efficiency and a reduction in
loss.
Further, if ferrite on the lower surface of the inner
circumferential coil 11a and ferrite on upper surfaces of the outer
circumferential coils 11b and 11c are separately provided,
interference between the high-frequency magnetic flux from the
inner circumferential coil 11a and the high-frequency magnetic
fluxes produced by the outer circumferential coils 11b and 11c is
reduced. This reduces loss in the non-contact power transmission
using the outer circumferential coils 11b and 11c as the power
feeding coils, thereby enabling an increase in power transmission
efficiency.
The inner circumferential coil 11a corresponds to a "first coil" of
the present invention.
Further, the inverter circuit 23 of the drive circuit 50a
corresponds to a "first inverter circuit" of the present invention,
and may include the direct-current power supply circuit 22 of the
drive circuit 50a.
Further, each of the outer circumferential coils 11b and 11c
corresponds to a "second coil" of the present invention.
Further, the inverter circuit 23 of the drive circuits 50b and 50c
corresponds to a "second inverter circuit" of the present
invention, and may include the direct-current power supply circuit
22 of the drive circuits 50b and 50c,
Further, the magnetic member 60a corresponds to a "first heating
element" of the present invention.
Further, the upper heater 61 corresponds to a "second heating
element" of the present invention.
Further, the control unit 45 corresponds to a "controller" of the
present invention.
Further, the first transmitting and receiving unit 30a corresponds
to a "receiving device" of the present invention.
Further, the second transmitting and receiving unit 30b corresponds
to a "transmitting device" of the present invention.
(Operation)
An operation of the inductive heating cooker of Embodiment 1 will
now be described.
A user places the food 70, such as fish, for example, on the
cooking tray 60b in the electric apparatus 200. The user places the
electric apparatus 200 on one of the heating areas of the top plate
4 of the main body 100. The following description will be given of
a case in which the electric apparatus 200 is placed on the first
heating area 1 (the first heating unit 11).
The user issues an instruction to start cooking (input heating
power) with the display-and-operation unit 43. The
display-and-operation unit 43 is installed with a dedicated mode
(menu) for operating the electric apparatus 200, and selecting the
dedicated mode enables easy cooking.
When the instruction to start cooking is issued, the control unit
45 of the main body 100 performs a heating operation of controlling
the drive circuit 50a in accordance with the heating power for
inductive heating, to thereby supply high-frequency power to the
inner circumferential coil 11a. Thereby, the magnetic member 60a
positioned on the lower surface of the cooking tray 60b of the
electric apparatus 200 is inductively heated. Then, the heat
generated in the magnetic member 60a by the inductive heating is
transferred to the non-magnetic cooking tray 60b, and the food 70
placed on the upper surface of the cooking tray 60b is directly
heated from below.
At the same time, the control unit 45 of the main body 100 performs
a power transmitting operation of controlling the drive circuits
50b and 50c in accordance with the electric power to be transmitted
to the power receiving coils 65, to thereby supply high-frequency
power to the outer circumferential coils 11b and 11c. Thereby, the
high-frequency power supplied by the outer circumferential coils
11b and 11c is received by the power receiving coils 65 positioned
on the lower surface of the electric apparatus 200. The received
power is supplied to the upper heater 61, and the upper heater 61
generates heat. Then, the upper heater 61 heats, from above, the
food 70 placed on the upper surface of the cooking tray 60b by
thermal radiation.
During the above-described heating operation, the control unit 45
may control the drive circuits 50a, 50b, and 50c in accordance with
the temperature detected by the temperature sensor 62.
For example, the control unit 45 may acquire the information of the
temperature detected by the temperature sensor 62 of the electric
apparatus 200 via the first transmitting and receiving unit 30a.
Then, the control unit 45 may control the driving of the drive
circuits 50a, 50b, and 50c in accordance with a temperature such as
a set temperature set with the display-and-operation unit 43 or a
temperature preset based on the cooking menu to adjust the
temperature in the heating chamber 210 of the electric apparatus
200 to a desired temperature, to thereby control the heat
generation amount (heating power) of each of the magnetic member
60a and the upper heater 61.
A plurality of temperature sensors 62 may be provided in the
vertical direction in the heating chamber 210. In this case, in
accordance with the temperature detected by one of the temperature
sensors 62 provided on the lower side, the control unit 45 controls
the heating power for inductively heating the magnetic member 60a
(the electric power to be supplied to the inner circumferential
coil 11a). Further, in accordance with the temperature detected by
one of the temperature sensors 62 provided on the upper side, the
control unit 45 controls the heating power of the upper heater 61
(the electric power to be supplied to the outer circumferential
coils 11b and 11c).
As described above, in Embodiment 1, the main body 100 of the
inductive heating cooker includes the drive circuit 50a configured
to supply a high-frequency current to the inner circumferential
coil 11a and the drive circuits 50b and 50c provided independently
of the drive circuit 50a and configured to supply a high-frequency
current to the outer circumferential coils 11b and 11c,
respectively. Further, the electric apparatus 200 of the inductive
heating cooker includes the magnetic member 60a configured to be
inductively heated by the inner circumferential coil 11a, the power
receiving coils 65 configured to receive electric power from the
outer circumferential coils 11b and 11c, and the upper heater 61
configured to generate heat with the electric power received by the
power receiving coils 65.
Therefore, heating through inductive heating and heating through
non-contact power transmission are simultaneously executable.
Further, the heating through inductive heating and the heating
through non-contact power transmission are independently
controllable. Accordingly, it is possible to obtain an inductive
heating cooker capable of nicely cooking food in a short time.
That is, with the drive circuit 50a and the drive circuits 50b and
50c provided independently of each other, it is possible to
independently control upper heating by the upper heater 61 and
lower heating with the heat from the magnetic member 60a, and thus
to obtain an inductive heating cooker capable of nicely cooking
food in a short time.
Further, the temperature sensor 62 configured to detect the
temperature in the heating chamber 210 of the electric apparatus
200 and the second transmitting and receiving unit 30b configured
to transmit the information of the detected temperature are
provided. The control unit 45 acquires the information of the
temperature detected by the temperature sensor 62 via the first
transmitting and receiving unit 30a. Then, in accordance with the
temperature detected by the temperature sensor 62, the control unit
45 controls the driving of the drive circuit 50a and the driving of
the drive circuits 50b and 50c.
The control unit 45 is therefore capable of independently
controlling the heating through inductive heating and the heating
through non-contact power transmission in accordance with the
temperature detected by the temperature sensor 62. Accordingly, it
is possible to finely control the internal temperature of the
electric apparatus 200 and the temperature of a cooking plate,
thereby enabling easy cooking with few failures.
In Embodiment 1, a description has been given of the outer
circumferential coils 11b and 11c, which include four coils.
However, the number of the coils is not limited thereto. Further,
although the four coils are driven by the two drive circuits 50,
the combinations of the coils and the drive circuits (inverter
circuits) are not particularly limited. Even if the four coils are
independently driven, effects similar to those described above are
obtained.
Further, in Embodiment 1, a description has been given of a case in
which the first heating unit 11 includes the inner circumferential
coil 11a and the outer circumferential coils 11b and 11c positioned
therearound. However, the present invention is not limited thereto.
It suffices if the coil for inductively heating the magnetic member
60a of the electric apparatus 200 and the coils for transmitting
electric power to the power receiving coils 65 of the electric
apparatus 200 are driven by the separate drive circuits 50
(inverter circuits).
Further, in Embodiment 1, a description has been given of a case in
which the electric apparatus 200 is placed on the top plate 4 of
the main body 100. However, the inner circumferential coil 11a and
the outer circumferential coils 11b and 11c may be used as
inductive heating coils to inductively heat the entire surface of
the heating area on which the heating target 5, such as a pot, is
placed. Thus inductively heating the entire surface of the heating
area enables an increase in area of an inductively heated area,
making it possible to obtain an inductive heating cooker capable of
sufficiently heating even a large pot.
Further, when inductively heating the placed heating target 5, such
as a pot, it is possible to independently control the electric
power to be input to the inner circumferential coil 11a and the
electric power to be input to the outer circumferential coils 11b
and 11c. It is therefore possible to change the inductively heated
area by sequentially switching between supply of power to the inner
circumferential coil 11a and supply of power to the outer
circumferential coils 11b and 11c. Such control enables convective
simmering when cooking food by simmering, making it possible to
obtain an inductive heating cooker capable of nicely cooking
food.
In Embodiment 1, a description has been given of the heating cooker
system including the main body 100 of the inductive heating cooker
and the electric apparatus 200. However, the present invention is
not limited thereto, and the entire configuration of the electric
apparatus 200 may be included in the main body 100 of the inductive
heating cooker to omit the electric apparatus 200. Further, the
configuration of the electric apparatus 200 may partially be
included in the main body 100 of the inductive heating cooker.
Modified Example 1
A modified example of the power receiving coil 65 will be
described.
FIGS. 7 and 8 are diagrams illustrating a modified example of the
power receiving coil of the electric apparatus according to
Embodiment 1.
The power receiving coil 65 in this modified example is formed of a
loop-shaped conductor 300, a coil 310, and a magnetic member 320.
Illustration of the magnetic member 320 is omitted in FIG. 8.
The loop-shaped conductor 300 is made of a conductive material such
as a metal having a low electrical resistance, such as aluminum or
copper. The loop-shaped conductor 300 is formed of an aluminum
plate or a copper plate, for example, which is processed into a
loop shape through processing such as cutting or pressing to form
an electrically closed circuit. The loop-shaped conductor 300 is
thereafter bent in a perpendicular direction at an intermediate
point in the longitudinal direction thereof to form an L shape. The
loop-shaped conductor 300 includes a horizontal portion 301 that is
positioned on the bottom surface of the electric apparatus 200 and
a vertical portion 302 that extends upward from an end of the
horizontal portion 301.
A back surface of the vertical portion 302 of the loop-shaped
conductor 300 is provided with the coil 310 formed of a conductive
wire wound into a flat plate shape. As illustrated in the drawings,
a coil bundle portion (a linear portion) forming a part of the coil
310 is positioned on a back surface of one of divided portions of
the vertical portion 302 of the loop-shaped conductor 300. Further,
another coil bundle portion (a linear portion) of the coil 310 is
positioned on a back surface of the other divided portion of the
vertical portion 302 of the loop-shaped conductor 300.
The magnetic member 320 is made of ferrite, for example, and is
positioned to form a magnetic circuit in which a high-frequency
magnetic flux produced when a high-frequency current is caused to
flow through the coil 310 interlinks with the loop-shaped conductor
300.
An operation will now be described.
Similarly as in the above description, when a high-frequency
magnetic flux (high-frequency magnetic field) is produced by the
corresponding one of the outer circumferential coils 11b and 11c,
electric power (electromotive force) due to electromagnetic
induction is generated in the loop-shaped conductor 300. With the
electromagnetic induction, therefore, an induced current flows
through the loop-shaped conductor 300. Further, owing to the low
electrical resistance of the loop-shaped conductor 300, a high
induced current flows through the loop-shaped conductor 300.
When a high-frequency induced current flows through the loop-shaped
conductor 300, a high-frequency magnetic flux .phi. is produced
around the loop-shaped conductor 300. In the vertical portion 302,
the high-frequency magnetic flux .phi. mostly passes through the
magnetic member 320 having a low magnetic resistance. In the
vertical portion 302, the magnetic circuit formed of the
loop-shaped conductor 300 and the magnetic member 320 is positioned
to make interlinkage with the coil 310. Thus, the high-frequency
magnetic flux .phi. interlinks with the coil 310. Consequently, an
induced current flows through the coil 310 owing to electromagnetic
induction. The induced current generated in the coil 310 is
supplied to the upper heater 61.
That is, the power receiving coil 65 illustrated in FIGS. 7 and 8
operates on the same operating principle as that of a transformer.
If the coil 310 is assumed to be primary winding, the number of
turns of which is N, the loop-shaped conductor 300 is secondary
winding, the number of turns of which is 1. Thus, the power
receiving coil 65 is assumable as a transformer in which N is 1.
Accordingly, a current having the same frequency as that of the
induced current induced by the loop-shaped conductor 300 flows
through the coil 310.
As described above, the loop-shaped conductor 300 of the power
receiving coil 65 is formed of a metal plate made of copper (not
coated with an insulating film).
Therefore, the heat resistance of the power receiving coil 65 per
se is improved, making it possible to ensure the heat resistance of
the power receiving coil 65 even if the temperature in the electric
apparatus 200 is increased to a high temperature. Accordingly, it
is possible to realize a high-temperature cooking menu, and thus to
obtain the electric apparatus 200 with an increase in the number of
cooking menus.
Further, since the power receiving coil 65 is improved in heat
resistance and formed of a thin metal plate, it is possible to
reduce the distance (interval) between the power receiving coil 65
and the cooking tray 60b of the cooking tray 60b. Accordingly, it
is possible to reduce the size of the electric apparatus 200, and
thus to obtain the electric apparatus 200 with a reduction in
weight and price.
Further, the coil 310 is positioned on the vertical portion 302 of
the loop-shaped conductor 300, and is connected to the upper heater
61 by the wires 61a (conductive wires). This makes it easy to
dispose the coil 310 and the wires 61a at respective positions to
which the heat from the heating chamber 210 is unlikely to be
transferred. Thus, a configuration promoting heat resistance is
obtainable.
Modified Example 2
Another configuration example of the drive circuit 50 will now be
described.
FIG. 9 is a diagram illustrating another one of the drive circuits
of the inductive heating cooker according to Embodiment 1.
The drive circuit 50a illustrated in FIG. 9 is formed of a
so-called full-bridge inverter, in which IGBTs 232a and 232b
serving as switching elements and diodes 232c and 232d serving as
flywheel diodes are additionally connected to the inverter circuit
23 in FIG. 4. The other configurations are similar to those in FIG.
4, and identical parts are assigned with identical reference
signs.
The control unit 45 outputs a drive signal for driving switching
elements (IGBTs 231a, 231b, 232a, and 232b) of the inverter circuit
23, and performs control similarly as in the above-described
operation such that the electric power input to the inner
circumferential coil 11a equals the electric power set for the
heating operation. Effects similar to those described above are
also obtainable with this configuration.
FIG. 9 illustrates an example of the drive circuit 50a that drives
the inner circumferential coil 11a. However, the configuration is
not limited thereto, and is also applicable to the other drive
circuits.
Modified Example 3
Further, another configuration example of the drive circuits 50
will be described.
FIG. 10 is a diagram illustrating the other ones of the drive
circuits of the inductive heating cooker according to Embodiment
1.
In the example illustrated in FIG. 10, the drive circuit 50b that
drives the outer circumferential coil 11b and the drive circuit 50c
that drives the outer circumferential coil 11c are formed of a
full-bridge inverter circuit in which one of arms forming a full
bridge is used as a shared arm.
As illustrated in FIG. 10, the drive circuits 50b and 50c are
formed of a full-bridge inverter similarly as in FIG. 9. The drive
circuits 50b and 50c are configured such that an arm formed of two
IBGTs 234a and 234b is used as a shared arm to perform the drive
control of the outer circumferential coil 11b (a power feeding
coil) with IGBTs 233a and 233b and the shared arm, and perform the
drive control of the outer circumferential coil 11c (a power
feeding coil) with IGBTs 235a and 235b and the shared arm.
This configuration is also capable of performing the drive control
of the outer circumferential coil 11b and the drive control of the
outer circumferential coil 11c, respectively, and obtaining effects
similar to those described above.
Modified Example 4
Another configuration example of the coils forming the first
heating unit 11 will now be described.
FIG. 11 is a diagram illustrating another first heating unit of the
inductive heating cooker according to Embodiment 1.
The first heating unit 11 illustrated in FIG. 11 is formed of the
inner circumferential coil 11a positioned at the center of the
heating area and an outer circumferential coil 11d positioned
substantially concentrically with the inner circumferential coil
11a.
Similarly as in the above description, the inner circumferential
coil 11a includes the inner circumferential inner coil 111a and the
inner circumferential outer coil 112a, which are connected in
series and subjected to the drive control of the drive circuit
50a.
The outer circumferential coil 11d includes an outer
circumferential inner coil 111d and an outer circumferential outer
coil 112d, which are formed concentrically with the inner
circumferential coil 11a. The outer circumferential inner coil 111d
and the outer circumferential outer coil 112d are connected in
series and subjected to drive control of a drive circuit 50d. The
configuration of the drive circuit 50d is similar to that of the
drive circuit 50a described above.
In this configuration example, the power receiving coils 65 of the
electric apparatus 200 are formed concentrically with the center of
the magnetic member 60a to correspond to the shape of the outer
circumferential coil 11d.
Also in this configuration, the inner circumferential coil 11a of
the main body 100 is used as an inductive heating coil for heating
the magnetic member 60a of the electric apparatus 200. Further, the
outer circumferential coil 11d is used as a power feeding coil for
performing non-contact power transmission to the upper heater 61 of
the electric apparatus 200. Thereby, effects similar to those
described above are obtainable.
Further, according to the present configuration, the coil
configuration is simpler than the above-described coil
configuration in FIG. 2. Therefore, effects similar to those
described above are obtainable with an inexpensive
configuration.
Embodiment 2
FIG. 12 is a block diagram illustrating a configuration of an
electric apparatus of a heating cooker system according to
Embodiment 2.
FIG. 12 schematically illustrates a longitudinal section of the
electric apparatus 200 viewed from a side surface side thereof, and
the configuration of the electric apparatus 200 is partially
omitted.
As illustrated in FIG. 12, the electric apparatus 200 of Embodiment
2 includes a drive mechanism 80 that moves the upper heater 61 in
the vertical direction.
The drive mechanism 80 is provided on a wall surface on a back
surface side of the housing, and is manually operated by the user,
for example, to move the upper heater 61 in the vertical direction.
For instance, the upper heater 61 is fixed to a rack formed of a
flat plate-shaped rod cut to have teeth, and a pinion engaging with
the rack is rotated to move the upper heater 61 in the vertical
direction.
The configuration of the drive mechanism 80 is not limited to the
one based on the manual operation. For example, the drive mechanism
80 may be configured to move the upper heater 61 with the drive
force of a motor. Further, the electric power received by the power
receiving coils 65 may be used as electric drive power of the motor
of the drive mechanism 80. Further, the electric apparatus 200 may
be provided with a storage battery, and the electric power received
by the power receiving coils 65 may be rectified and thereafter
stored in the storage battery to be used as the electric drive
power of the drive mechanism 80.
As described above, in Embodiment 2, the electric apparatus 200
includes the drive mechanism 80 that moves the upper heater 61 in
the vertical direction.
It is therefore possible to change the position (height) of the
upper heater 61 in accordance with factors such as the height,
thickness, and size of the food 70. Accordingly, it is possible to
change the amount of radiant heat from the upper surface of the
food 70, thereby enabling heating control according to cooking,
cooking in a short time, and an increase in types and ranges of
cooking, such as browning the cooked food.
Embodiment 3
FIGS. 13 and 14 are block diagrams illustrating a configuration of
an electric apparatus of a heating cooker system according to
Embodiment 3.
FIG. 15 is a top view schematically illustrating the configuration
of the electric apparatus of the heating cooker system according to
Embodiment 3.
FIGS. 13 and 14 illustrate a state in which the electric apparatus
200 is placed on the top plate 4 of the main body 100. Further,
FIG. 13 schematically illustrates a longitudinal section of the
main body 100 and the electric apparatus 200 viewed from a front
surface side thereof. Further, FIG. 14 schematically illustrates a
longitudinal section of the main body 100 and the electric
apparatus 200 viewed from a side surface side thereof.
The following description will focus on differences from Embodiment
1 described above.
As illustrated in FIGS. 13 to 15, each of the magnetic member 60a
and the cooking tray 60b in Embodiment 3 is formed into a
rectangular shape in a top view. The magnetic member 60a and the
cooking tray 60b are formed such that each of long sides thereof
has a length equal to or greater than the width of the
corresponding heating area, for example, and that each of short
sides thereof has a length substantially equal to the width (outer
diameter) of the inner circumferential coil 11a.
For example, when the electric apparatus 200 is placed on the top
plate 4 such that the long sides of the magnetic member 60a and the
cooking tray 60b are oriented along the lateral direction, left end
portions of the magnetic member 60a and the cooking tray 60b are
positioned outside an end portion of the outer circumferential left
coil 111b of the main body 100, and that right end portions of the
magnetic member 60a and the cooking tray 60b are positioned outside
the outer circumferential right coil 112b of the main body 100, as
illustrated in FIGS. 13 and 14. Further, the width in the
anteroposterior direction of each of the magnetic member 60a and
the cooking tray 60b is substantially equal to the width of the
inner circumferential coil 11a. That is, each of the magnetic
member 60a and the cooking tray 60b has a shape that is not
superimposed on the outer circumferential upper coil 111c and the
outer circumferential lower coil 112c.
The power receiving coils 65 of Embodiment 3 are positioned to
flank the two long sides of each of the magnetic member 60a and the
cooking tray 60b, for example. The power receiving coils 65 are two
power receiving coils 65 provided to correspond to the outer
circumferential upper coil 111c and the outer circumferential lower
coil 112c of the main body 100. Each of the two power receiving
coils 65 has a substantially quarter arcuate shape (banana or
cucumber shape) in a plan view, and is formed of a conductive wire
made of a given metal (copper or aluminum, for example) coated with
an insulating film and wound along the quarter arcuate shape of the
power receiving coil 65.
FIG. 16 is a diagram illustrating a first heating unit of an
inductive heating cooker according to Embodiment 3.
In FIG. 16, the configuration of the first heating unit 11 is
similar to that of Embodiment 1 described above, but the drive
control of the first heating unit 11 by the control unit 45 is
different from that of Embodiment 1.
That is, the control unit 45 performs a heating operation of
controlling the drive circuit 50a that drives the inner
circumferential coil 11a and the drive circuit 50b that drives the
outer circumferential coil 11b (the outer circumferential left coil
111b and the outer circumferential right coil 112b) in accordance
with the heating power for inductive heating, to thereby supply
high-frequency power. Thereby, the magnetic member 60a positioned
on the lower surface of the cooking tray 60b of the electric
apparatus 200 is inductively heated. Then, the heat generated in
the magnetic member 60a by the inductive heating is transferred to
the non-magnetic cooking tray 60b, and the food 70 placed on the
upper surface of the cooking tray 60b is directly heated from
below.
At the same time, the control unit 45 performs a power transmitting
operation of controlling the drive circuit 50c in accordance with
the electric power to be transmitted to the corresponding power
receiving coils 65, to thereby supply high-frequency power to the
outer circumferential coil 11c (the outer circumferential upper
coil 111c and the outer circumferential lower coil 112c). Thereby,
the high-frequency power supplied by the outer circumferential coil
11c is received by the corresponding power receiving coils 65
positioned on the lower surface of the electric apparatus 200. The
received power is supplied to the upper heater 61, and the upper
heater 61 generates heat. The upper heater 61 then heats, from
above, the food 70 placed on the upper surface of the cooking tray
60b by thermal radiation.
As described above, in Embodiment 3, the respective widths of the
magnetic member 60a and the cooking tray 60b are increased to be
greater than those in Embodiment 1 described above, and the
magnetic member 60a is inductively heated by the inner
circumferential coil 11a and the outer circumferential coil 11b.
With an increase in the area of lower heating through inductive
heating, therefore, it is possible to add appropriate browning to
food from below. For example, even if the food 70 is of an
elongated shape, such as fish, it is possible to place the food 70
on the cooking tray 60b and nicely cook the food 70, such as fish,
by lower heating.
Herein, the power feeding coils for supplying electric power to the
upper heater 61 of the electric apparatus 200 are the outer
circumferential upper coil 111c and the outer circumferential lower
coil 112c. As compared with the configuration in FIG. 4, the number
of coils for supplying electric power to the power receiving coils
65 is reduced. To prevent a reduction in the electric power
supplied to the upper heater 61, therefore, the electric power to
be supplied to the outer circumferential upper coil 111c and the
outer circumferential lower coil 112c is increased. Accordingly, it
is possible to obtain the electric apparatus 200 capable of nicely
cooking food in a short time without compromising the cooking
time.
Further, if the drive mechanism 80 of Embodiment 2 described above
is applied to move the upper heater 61 toward the food 70, it is
possible to obtain the electric apparatus 200 capable of nicely
cooking food in a short time without compromising the cooking
time.
Embodiment 4
In Embodiment 4, a description will be given of an operation of
detecting whether any of the magnetic member 60a and the power
receiving coils 65 of the electric apparatus 200 is placed above
the coils of the main body 100, and switching between the heating
operation and the power transmitting operation in accordance with
the result of the detection.
In Embodiment 4, the configuration of the main body 100 is similar
to that of Embodiment 1 described above, and the configuration of
the electric apparatus 200 is similar to that of one of Embodiments
1 to 3 described above.
When the user places the electric apparatus 200 on one of the
heating areas and issues an instruction to start heating (input
heating power) with the display-and-operation unit 43, the control
unit 45 (a load determining unit) performs a load determining
process.
The control unit 45 of Embodiment 4 includes the function of a
"load determining unit" of the present invention.
FIG. 17 is a load determining characteristic graph based on the
relationship between a coil current and an input current in an
inductive heating cooker according to Embodiment 4.
As illustrated in FIG. 17, the relationship between the coil
current and the input current changes depending on the material of
the load placed above the corresponding one of the coils (the inner
circumferential coil 11a and the outer circumferential coils 11b
and 11c) of the main body 100. The control unit 45 previously
stores therein a load determining table, which is a table of the
relationship between the coil current and the input current
illustrated in FIG. 17. With the load determining table stored in
the control unit 45, it is possible to configure the load
determining unit with an inexpensive configuration.
In the load determining process, the control unit 45 drives the
inverter circuit 23 of each of the drive circuits 50a to 50c with a
specific drive signal for load determination, and detects the input
current from the signal output from the input current detecting
unit 25a. At the same time, the control unit 45 detects the coil
current from the signal output from the coil current detecting unit
25b. The control unit 45 determines the material of the load placed
above the corresponding coil from the detected coil current, the
detected input current, and the load determining table representing
the relationship of FIG. 17.
If the result of the load determination indicates that the material
of the load is a magnetic material, the control unit 45 determines
that the magnetic member 60a of the electric apparatus 200 is
placed above the coil. Further, if the result of the load
determination indicates that the material of the load is other than
the magnetic material, the control unit 45 determines that one of
the power receiving coils 65 is placed above the coil. Further, if
the result of the load determination indicates that there is no
load, the control unit 45 determines that none of the magnetic
member 60a and the power receiving coils 65 is placed
thereabove.
The control unit 45 then performs a heating operation of
controlling the drive circuit 50 that drives the one of the inner
circumferential coil 11a and the outer circumferential coils 11b
and 11c determined to have the magnetic member 60a placed
thereabove, to thereby supply high-frequency power according to the
heating power for inductive heating.
At the same time, the control unit 45 performs a power transmitting
operation of controlling the drive circuit 50 that drives the one
of the inner circumferential coil 11a and the outer circumferential
coils 11b and 11c determined to have one of the power receiving
coils 65 placed thereabove, to thereby supply high-frequency power
according to the electric power to be transmitted to the power
receiving coil 65.
The control unit 45 stops the operation of the drive circuit 50
that drives the coil determined to have no load placed
thereabove.
Subsequent operations are similar to those of Embodiment 1
described above.
As described above, in Embodiment 4, whether any of the magnetic
member 60a and the power receiving coils 65 is placed above the
coils is determined, and the heating operation or the power
transmitting operation by the coils is performed in accordance with
the result of the detection. Accordingly, it is possible to
automatically perform an operation according to the configuration
and arrangement of the magnetic member 60a and the power receiving
coils 65 in the electric apparatus 200.
The above description has been given of a case in which the load
determination is performed based on the correlation between the
input current and the coil current. However, the present invention
is not limited thereto, and may employ a given load determining
process. For example, the frequency of the high-frequency current
to be supplied to the coils may be continuously changed, and the
load determination may be performed based on change characteristics
of the input current during the change.
Embodiment 5
FIG. 18 is a perspective view illustrating a schematic
configuration of a main body of an inductive heating cooker
according to Embodiment 5.
As illustrated in FIG. 18, in the main body 100 of the inductive
heating cooker according to Embodiment 5, a plurality of coils 120
each having a relatively small size are positioned under the top
plate 4 to be substantially evenly dispersed.
Each of the plurality of coils 120 is independently driven by a
corresponding drive circuit 50. The configuration of the drive
circuit 50 that drives the coil 120 is similar to the configuration
of the drive circuit 50a of Embodiment 1 described above, for
example.
Further, for each of the plurality of coils 120, the control unit
45 of Embodiment 5 performs load determination of the load placed
thereabove. The load determining process is similar to that of
Embodiment 4 described above.
In the configuration of Embodiment 5, the marks of the heating
areas may not be provided on the top plate 4. The number of the
coils 120 may be any number. Further, the layout of the coils 120
is not limited to the above-described one. The coils 120 may be
arranged in a honeycomb pattern, or may include large coils 120 and
small coils 120 mixedly arranged.
(Operation)
When the user places the electric apparatus 200 at a given position
on the top plate 4 and issues an instruction to start heating
(input heating power) with the display-and-operation unit 43, the
control unit 45 (the load determining unit) performs a load
determining process.
With an operation similar to that of Embodiment 4 described above,
the control unit 45 performs, for each of the plurality of coils
120, the load determining process of determining the material of
the load placed thereabove.
If the result of the load determination indicates that the material
of the load is a magnetic material, the control unit 45 determines
that the magnetic member 60a of the electric apparatus 200 is
placed above the coil 120. Further, if the result of the load
determination indicates that the material of the load is other than
the magnetic material, the control unit 45 determines that one of
the power receiving coil 65 is placed above the coil 120. Further,
if the result of the load determination indicates that there is no
load, the control unit 45 determines that none of the magnetic
member 60a and the power receiving coils 65 is placed
thereabove.
The control unit 45 then performs a heating operation of
controlling the drive circuit 50 that drives the one of the
plurality of coils 120 determined to have the magnetic member 60a
placed thereabove, to thereby supply high-frequency power according
to the heating power for inductive heating.
At the same time, the control unit 45 performs a power transmitting
operation of controlling the drive circuit 50 that drives the one
of the plurality of coils 120 determined to have one of the power
receiving coils 65 placed thereabove, to thereby supply
high-frequency power according to the electric power to be
transmitted to the power receiving coil 65.
The control unit 45 stops the operation of the drive circuit 50
that drives the one of the plurality of coils 120 determined to
have no load placed thereabove.
Subsequent operations are similar to those of Embodiment 1
described above.
As described above, Embodiment 5 includes the plurality of coils
120 positioned under the top plate 4 to be substantially evenly
dispersed. Further, the control unit 45 detects, for each of the
plurality of coils 120, whether any of the magnetic member 60a and
the power receiving coils 65 is placed thereabove. The control unit
45 then performs the heating operation or the power transmitting
operation by the coils 120 in accordance with the result of the
detection. Accordingly, it is possible to automatically perform an
operation according to the configuration and arrangement of the
magnetic member 60a and the power receiving coils 65 in the
electric apparatus 200.
Further, it is possible to place the electric apparatus 200 at a
given position on the top plate 4, and thus to improve
convenience.
REFERENCE SIGNS LIST
1 first heating area 2 second heating area 3 third heating area 4
top plate 5 heating target 11 the first heating unit 11a inner
circumferential coil 11b outer circumferential coil 11c outer
circumferential coil 11d outer circumferential coil 12 second
heating unit 13 third heating unit 21 alternating-current power
supply 22 direct-current power supply circuit 22a diode bridge 22b
reactor 22c smoothing capacitor 23 inverter circuit 23a, 23b IGBT
23c, 23d diode 24a, 24c, 24d resonant capacitor 25a input current
detecting unit 25b, 25c, 25d coil current detecting unit 30a first
transmitting and receiving unit 30b second transmitting and
receiving unit 40 operation unit 40a to 40c operation unit 41
display unit 41a to 41c display unit 42 reporting unit 43
display-and-operation unit 45 control unit 50 drive circuit 50a to
50d drive circuit 60a magnetic member 60b cooking tray 61 upper
heater 61a wire 62 temperature sensor 65 power receiving coil
cooked food 80 drive mechanism 100 main body 111a inner
circumferential inner coil 111b outer circumferential left coil
111c outer circumferential upper coil 111d outer circumferential
inner coil 112 outer circumferential lower coil 112a inner
circumferential outer coil 112b outer circumferential right coil
112c outer circumferential lower coil 112d outer circumferential
outer coil 120 coil 200 electric apparatus 210 heating chamber
231a, 231b, 232a, 232b, 233a, 233b, 234a, 234b, 235a, 235b IGBT
231c, 231d, 232c, 232d, 233c, 233d, 234c, 234d, 235c, 235d diode
300 loop-shaped conductor 301 horizontal portion 302 vertical
portion 310 coil 320 magnetic member
* * * * *